When revolution first came to Syria, Loubna Mrie decided she would break new ground to help it succeed.

Deeply affected by the images of dead protesters across the country, the 21-year-old Alawite – the daughter of a leader of the regime's thuggish Shabiha militia and member of Syria's most privileged minority – left her home in the regime heartland of Latakia and travelled to parts of Syria where death tolls were mounting.

She soon became a feature at demonstrations and even ventured near the frontlines of the regime's fight with an armed opposition, delivering medicines to wounded rebels and finding homes for fleeing families.

In August, Mrie appeared in a web video, her face wrapped in the independence flag adopted by the opposition. She was injured at a demonstration in which nine fellow protesters were killed. Every step she took to support those fighting four decades of state control earned the increasing wrath of close relatives. Every move made her more vulnerable.

Last week the revolution took a toll that not even 19 months of exile and enmity had prepared her for. "I learned that my mother is dead," she said. "And it was my father that killed her."

Alone in a house in Turkey, Mrie now feels racked with guilt. "My mother was kidnapped immediately after I made the video with the rebels on August 11," she said. "I waited for 10 days. I begged my father to tell me what he knew about it, to let me know. He used to curse me and hang up the phone. Some of my dad's friends told me that she was dead.

"Last Friday [2 November] one of my friends, someone that I trust, told me that the dead body had been seen. I called [my father] and told him that he killed her. He said OK. He told me that he wished he could do the same to me."

The Guardian was unable to independently verify Mrie's claim that her mother had been killed.

Mrie has been told to stay well away from her home village of Jableh and cannot verify for herself that her mother is dead. But she needs no more convincing. "People I trust are telling me that she's gone," she said.

Early last week, she posted on Facebook a lament to her late mother and to the father that she believes has killed her. The post has drawn widespread sympathy among opposition circles, where Alawite supporters are extremely rare and almost always silent.

"They hit her because of me. Was it by electricity or a single bullet in her head?" the post asked. "Was she upset at me when they were humiliating her? Did her old age stop them from hurting her?

"Abu Muntazer [her father] went to his brothers, cheered them up and told them that he washed the shame that his daughter brought to Jebel al-Akrud [the mountains near Latakia where the video was filmed] ...

"I hate my identity and my passport. I hate your name which will accompany mine. What should I say to my future kids about why I don't have a family? Why isn't there a grave for my mum? Why this double punishment? Why the injustice?"

Loubna Mrie fears that the Alawites have been co-opted by a regime that wants to retain power by instilling fear in them. Photograph: Ben Solomon

Yet even in the face of grief that seems impossible to fathom and guilt that has at times been overwhelming, Mrie retains a streak of defiance. She has continued her work in a small unit that acts as a clearing house for mobile phone videos smuggled out of Syria.

The sense of necessary sacrifice that led her to join the opposition in the early days continues to drive both Mrie and a small number of other Alawite members of the opposition, who fear that their sect has been co-opted by a regime that wants to retain power by instilling fear in them.

"On the first day of the revolution, I cried like it was one of my family members. And from that day I decided that we can not go on like that. My people are not really living. The government does not respect us. The mukhabarat [secret police] has taken over our lives. We can't open our mouths."

Latakia is a particularly pro-regime area. The Assad regime draws much of its support from communities there, which have long been prime recruitment grounds for Shabiha members. The Shabiha is a loyalist militia that fiercely defends regime interests and has been in the vanguard of the regime crackdown.

"All the Shabiha in Jableh were boys I had grown up with. At the time they were trying to convince me that this was a war against us as minorities and that we had to stop talking to the Sunnis."

Syria's Sunni majority dominates the opposition. The regime is supported by most of the Alawite sect, who make up the vast majority of Syria's military leadership and establishment but only account for around 12% of the population.

Alawites have loose links to Shia Islam, a fact that inspires some extremist groups on the fringes of the opposition to frame the revolution as an existential battle along the ancient faultline between Shias and Sunnis.

A majority of Christians also appear to support the regime, along with a sizeable number of the Sunni population, including much of the merchant class, as well as senior military and Ba'ath party officials.

"I started to go to the houses of the dead people," Mrie said. " At the time there was a huge gap between them and the Alawites. Both were convinced that each side was fighting the other.

"For six months I tried my best to raise awareness that this revolution is not against us. We were fighting for dignity and democracy.

"In January I went to Hama and spoke in the name of my sect. I wanted to tell them that my blood is theirs. My father used to tell me that I was a criminal and that he was ashamed of me and that he didn't see me as his daughter.

"The stupid thing about this government is its claim that it is trying to protect the people, that it is protecting the Alawites. [Assad] doesn't care if you are Alawite, Christian or Shia. If you are against him, he will kill you."

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